The field of the present invention is devices for collecting oral fluid samples. In particular, the present invention provides a device having an absorbent for collection of oral fluids thereon and the absorbent having a shield layer positioned adjacent to one side of the absorbent. The shield operates to support the absorbent and to prevent adhesion of the absorbent to the oral tissue or the teeth while the absorbent is within the mouth for collection of an oral fluid sample. In one embodiment of the invention the shield operates to insure that the only oral fluid contacting the absorbent during the collection procedure is saliva. A method of collecting saliva from the buccal cavity is provided which avoids the collection of mucosal transudate.
The buccal cavity of the mouth is that portion of the mouth between the inside of the cheek and the teeth and gums. It has long been recognized that the buccal cavity is a convenient location for the collection of saliva from human beings. One prior example of the use of the buccal cavity as a saliva collection area can be found in Immunoradiometric Assay of Salivary Anti-C3 Antibodies, by Challacombe, Journal of Immunological Methods, (1978), pages 53-59. In the Challacombe article, saliva was collected from neonates by means of a small sterile sponge placed in the mouth between the gum and the cheek. Numerous other methods and devices for collecting saliva have been utilized throughout the years. Typically, these methods for collecting saliva have comprised placement of an absorbent pad or a wad chewable material in the mouth to absorb saliva as the material rested in the mouth or was chewed by the subject.
Recently, investigators have been attracted to methods and devices for collecting oral mucosal transudate (OMT) for the collection and measurement of various analytes which may be present in a subject. Typically the device used for such mucosal transudate collection has consisted of a cotton fiber pad that is placed between the lower gum and cheek and rubbed back and forth along the gum/teeth margin (the gingival interface) followed by analysis of the material absorbed on the cotton wool swab. An example of this type of collection of material on a cotton wool swab from along the gum/teeth margin can be found in diagnosis of Hepatitis A and B by testing saliva, J. V. Parry, et al., Journal of Medical Virology, 28:255-60 (1989).
During the collection of saliva from the mouth, and in particular, the buccal cavity, it is not uncommon for the absorbent to be placed into the buccal cavity or under the tongue and to be allowed to reside there for two or more minutes. During this period of time that saliva is being collected from the mouth, moisture is being removed from the tissue surrounding the absorbent and drawn into the pad. It is not uncommon for this loss of moisture from the tissues adjacent the pad to result in the absorbent pad beginning to adhere or stick to the tissue of the mouth thereby making removal of the absorbent pad difficult or uncomfortable. It is possible for the adhesion of the absorbent pad to the mouth tissue to be sufficiently strong that the attempt to withdraw the absorbent pad from the mouth results in separation of the pad from the handle portion of the apparatus being used to manipulate the absorbent pad. In particular, it is not uncommon that the absorbent pad will be placed in the buccal cavity, and the side of the absorbent pad which is next to the teeth and gums will become stuck to the teeth or the gum tissue. This circumstance is uncomfortable for the patient and can result in separation of the absorbent pad from the handle when removal of the saliva saturated absorbent pad from the mouth is attempted.
The present invention solves the problem of adhesion of the absorbent pad to oral tissue and at the same time provides a support structure to prevent un-wanted tearing of the absorbent away from the device handle. Further, the present invention provides investigators with a means of isolating fluid absorption from areas of the mouth from which collection is not desired. In particular, one embodiment of the present invention prevents the absorbent from contacting the gingival interface at the junction of the teeth and gums and thereby prevents collection of OMT or oral mucosal transudate.
The present invention eliminates or greatly reduces the instances of adhesion of an absorbent pad to tissues that are adjacent to one side of the pad. Also, the present invention provides additional structural support for an absorbent pad once it has become saturated with an oral fluid such as saliva. A further advantage of the present invention is that one side of the absorbent pad can be shielded from contact with adjacent oral tissues thereby preventing absorption of an oral fluid onto the shielded side of the absorbent pad as a result of direct contact by the pad with the adjacent oral tissue.
The above benefits and objectives are accomplished in the present invention by an oral fluid collection device which provides, in one embodiment, a non-absorbent layer or shield which is applied to, or is adjacent to, one side of an absorbent pad. In another embodiment, a different combination of the benefits of the present invention are accomplished by use of a fluid shield or fluid-impervious layer which is provided with voids in the shield layer. The voids allow analytes that are dissolved in saliva to pass through the shield layer and to be absorbed by the pad while the shield prevents adhesion of the absorbent to the adjacent oral tissue. In addition, mouth fluids which must be rubbed off of tissues (e.g., OMT) are not collected by the pad.
The foregoing and other objects are intended to be illustrative of the invention and are not meant in a limiting sense. Many possible embodiments of the invention may be made and will be readily evident upon a study of the following specification and accompanying drawings comprising a part thereof. Various features and subcombinations of invention may be employed without reference to other features and subcombinations. Other objects and advantages of this invention will become apparent from the following description taken in connection with the accompanying drawings, wherein is set forth by way of illustration and example, an embodiment of this invention.